mechanics

Question 1

centre of mass

Answer 1

the point through which a single force acting on the body has no turning effect

Question 2

couple

Answer 2

want an object to rotate but do not want its centre of mass to accelerate

Question 3

average speed

Answer 3

total distance/ time

Question 4

average velocity

Answer 4

total displacement/ time

Question 5

what causes drag

Answer 5

partly by the friction between layers of air molecules near projectile surface

Question 6

newtons 3rd law pairs

Answer 6

act on 2 separate bodies
same type of force
same magnitude
act along the same line
act in opposite direction

Question 7

gradient for displacement time graph

Answer 7

velocity

Question 8

tangent for displacement time graph

Answer 8

instantaneous velocity

Question 9

gradient for velocity time graph

Answer 9

acceleration

Question 10

tangent for velocity time graph

Answer 10

instantaneous acceleration

Question 11

area under the graph for a velocity time graph

Answer 11

displacement

Question 12

area under an acceleration time graph

Answer 12

velocity

Question 13

in projectile motion, what is independent of one another

Answer 13

horizontal and vertical motion

Question 14

terminal velocity

Answer 14

• weight > friction

-as v increases, fr increases , which causes the resultant force to decrease and acceleration decreases

• weight = friction (now have a terminal velocity)

-(parachute opens) - friction > weight , therefore, the person slows down

-weight = friction and get a new terminal velocity

Question 15

impulse

Answer 15

force that causes a change in momentum

Question 16

what is the area under a force time graph

Answer 16

impulse

Question 17

what is the law of conservation of momentumn

Answer 17

in an isolated system, the total linear momentum is always conserved

Question 18

elastic collisions

Answer 18

ek is conserved

Question 19

inelastic collisions

Answer 19

ek is not conserved

Question 20

explosions

Answer 20

ek is not conserved

Question 21

principle of conservation

Answer 21

energy cant be created or destroyed

Question 22

potential energy

Answer 22

the energy an object possess because of its position or configuration

Question 23

constant

Answer 23

t = w

Question 24

accel up

Answer 24

t > w

Question 25

accel down

Answer 25

w > t

Question 26

decel down

Answer 26

t > w

Question 27

decel up

Answer 27

w > t